Daptomycin Dosing Based on Adjusted Body Weight in Obese Patients versus Actual Body Weight: A Multicentre Cohort Study

Purpose: Daptomycin-approved dosing is based on actual body weight (ABW). However, the pharmacokinetics and pharmacodynamics of daptomycin are altered in obese patients, leading to increased daptomycin exposure owing to incomplete distribution into excess body tissues. Data regarding the use of alternative weight descriptors for daptomycin dosing are limited. This study aimed to investigate the effectiveness and safety of daptomycin in obese patients by using adjusted body weight (AdjBW). Methods: This retrospective multicenter cohort study in Saudi Arabia compared the outcomes of obese patients who received daptomycin based on AdjBW with those of obese and non-obese patients who received daptomycin based on ABW. The main outcomes included clinical cure, overall in-hospital mortality, and 30-day mortality. The safety outcomes were evaluated. Multivariate logistic regression was used to control for confounding variables. Results: A total of 293 patients met the inclusion: 43 patients in AdjBW group, 54 in the ABW group, and 196 in the non-obese group. When comparing the AdjBW and ABW obese groups, no statistically significant difference was observed in clinical cure (83.7% vs 77.8%; p = 0.461; OR, 0.1.47; 95% CI, 0.52-4.12), overall in-hospital mortality (23.3% vs 35.2%; p = 0.200; OR, 0.56; 95% CI, 0.23-1.37), or 30-day mortality (16.3% vs 27.8%; p = 0.174; OR, 0.51; 95% CI, 0.19-1.38). Creatine phosphokinase elevation (8.6% vs 6%; p = 0.651) was similar between the two groups. Similar outcomes were observed when comparing the AdjBW and non-obese groups. Conclusion: Treatment with daptomycin based on AdjBW in obese patients had similar effectiveness and safety outcomes as treatment with daptomycin based on ABW in obese and non-obese patients. Therefore, future prospective studies are warranted.